The present disclosure relates generally to semiconductor devices and, more particularly, to image sensors having an embedded bonding pad.
In semiconductor technologies, image sensors are used for sensing a volume of exposed light projected towards a semiconductor substrate. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) and charge-coupled device (CCD) sensors are widely used in various applications such as digital still camera applications. These devices utilize an array of pixels or light-sensing elements, including photodiodes and transistors, to collect photo energy to convert images into electrical signals. In order to capture color information, image sensors may employ a color filter layer that incorporates several different color filters (e.g., red, green, and blue), and are positioned such that the incident light is directed through the filter via a micro-lens. The color filter layer and micro-lens are formed at a top surface of the image sensors.
However, bonding pads are also formed near the top surface of the image sensors for use in wafer level testing and wire bonding during chip packaging. As such, a profile or topography of the bonding pad may adversely effect the process of forming the color filter layer and micro-lens. Further, the thickness of the bonding pad adds to the distance that light must travel in order to reach the pixels and, thus, may degrade a photosensitivity of the image sensors.